In a large pot, heat a tbsp of olive oil over medium heat. Add onions and garlic, sauté until fragrant and soft.
Add sweet potato, carrots, celery, and butternut squash. Stir and cook for 5-7 minutes until the vegetables start to soften.
Sprinkle cumin, sweet paprika, garam masala, turmeric and black pepper over the vegetables. Stir well to coat the veggies evenly with the spices.
Add the rinsed red lentils to the pot.
Pour in the vegetable broth, ensuring it covers all the ingredients. Bring the mixture to a gentle boil.
Reduce the heat to low and let the soup simmer for about 20-25 minutes until the lentils and veggies are tender.
For a creamy texture, use an immersion blender to partially blend the soup. If you prefer a chunky soup, skip this step.
6 servings